CN111716983A

CN111716983A - Control system for a thermal system and method for operating a thermal system

Info

Publication number: CN111716983A
Application number: CN202010159723.1A
Authority: CN
Inventors: R·赫博尔茨海默; O·霍恩; P·奥斯瓦尔德; M·施蒂克斯
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 2019-03-20
Filing date: 2020-03-10
Publication date: 2020-09-29
Also published as: US11390138B2; DE102019107192A1; US20200298653A1; DE102019107192B4

Abstract

The present invention relates to a control system for a thermal system of a vehicle. The control system is designed such that, in the event of a cooling requirement for the interior, an air-conditioning cooling operation is set for cooling the interior by means of an air-conditioning evaporator of the thermal system; adjusting to an HVS cooling operation in the case of a cooling requirement for the high-pressure accumulator for cooling the high-pressure accumulator by means of a radiator of the thermal system; in the case of simultaneous HVS cooling operation and air-conditioning cooling operation, the compressor of the refrigeration circuit is regulated by means of a regulating variable, which is the setpoint air temperature at the evaporator of the air conditioner; and actuating the expansion valve in accordance with the manipulated variable for the compressor in the case of both an HVS cooling operation and an air-conditioning cooling operation, or using a further manipulated variable in the case of an HVS cooling operation without an additional air-conditioning cooling operation for the compressor, or both. The invention also relates to a method for operating a vehicle thermal system by means of such a control system.

Description

Control system for a thermal system and method for operating a thermal system

Technical Field

The present invention relates to a control system for a thermal system of an electric or hybrid vehicle and to a method for operating such a thermal system by means of such a control system.

Background

Thermal systems are generally used for temperature control of various components, which are connected to the thermal system for this purpose. In particular in electric or hybrid vehicles, such components are the interior of the vehicle, the high-pressure accumulator of the vehicle and one or more heat sources of the electric drive train of the vehicle, for example an electric machine or power electronics, or the like. The thermal system can generally be operated in various operating states in order to handle the respective temperature control requirements of the individual components. It is problematic that there are generally a plurality of components which simultaneously generate different temperature control requirements.

DE102015218825a1 describes a control system which enables a heating operation and a cooling operation for a vehicle interior. In heating operation, heat can be absorbed from the environment by means of the heat pump and can be used for heating the interior via the heating heat exchanger. In cooling operation, the heat pump is deactivated and the air conditioning evaporator is activated for cooling the interior. The heat pump includes a radiator commonly connected in the refrigeration circuit with the air conditioning evaporator. In addition to the radiator and the air conditioning evaporator, a further evaporator is connected to the refrigeration circuit for cooling the high-pressure accumulator of the vehicle.

Disclosure of Invention

Against this background, it is an object of the present invention to provide an improved control system for a thermal system. Furthermore, an improved method for operating a thermal system is to be specified. In particular, the cooling of the high-pressure accumulator of the vehicle should be carried out as efficiently as possible by means of the coolant. At the same time, it is also intended to achieve as efficient and as satisfactory as possible an air conditioning of the interior, in particular by means of a heat pump.

The object is achieved by a control system having the features according to claim 1 and by a method having the features according to claim 14. Advantageous embodiments, further developments and variants are the subject matter of the dependent claims. Embodiments in combination with a control system are also applicable to the method according to the meaning, and vice versa.

The control system is used for controlling a thermal system of an electric or hybrid vehicle, which is hereinafter simply referred to as vehicle. The vehicle has a high-pressure reservoir cooled with coolant. For the purpose of control, the control system is in particular combined with, that is to say preferably connected to, a thermal system. This is understood in particular to mean that the control system operates and regulates the thermal system by means of a number of regulating elements. The thermal system has in particular a number of components for air conditioning of the vehicle. These components are controlled or regulated or both by the control system and are therefore the regulating elements of the control system. In this sense, the vehicle is air-conditioned by means of a control system, which controls or regulates the thermal system or both.

In this case, it is important, in particular, to regulate the compressor, rather than merely control or simply set a constant compressor rotational speed.

The control system is designed such that, in the event of a cooling requirement for the interior of the vehicle, an air-conditioning cooling operation of the thermal system is set up for cooling the interior by means of an air-conditioning evaporator of a refrigeration circuit of the thermal system, and, in the event of a cooling requirement for the high-pressure reservoir of the vehicle, an HVS cooling operation of the thermal system is set up for cooling the high-pressure reservoir by means of a radiator (Chiller) of the thermal system. The radiator is connected upstream in the refrigeration circuit to an expansion valve by means of which the heat absorbed by the radiator into the refrigeration circuit can be adjusted. The air-conditioning cooling operation and the HVS cooling operation are each one operation mode of the thermal system. In this way, the cooling requirements for the interior space and the high-pressure accumulator can be handled independently of one another and in particular also simultaneously during operation of the thermal system, by activating, i.e. adjusting to the respective operating mode. In addition, in one variant, one or more further operating modes can be set.

Furthermore, the control system is in particular designed such that the refrigeration circuit of the thermal system is controlled as a function of whether the air-conditioning cooling operation or the HVS cooling operation is set or both are set. In other words: the control or regulation of one or more components of the refrigeration circuit is effected, wherein the refrigeration circuit is controlled by means of a control system in order to optimally handle the respective cooling demand and the control is adapted to the operating mode to which it is set and to which it is not set. Thus, depending on the operating mode, the components are controlled or regulated or a combination thereof depending on the operating mode. The refrigeration circuit is thus optimally adjusted at a given point in time with regard to the overall situation, which is defined by the sum of all activated operating modes. This makes it possible to resolve possible target conflicts in the allocation of power to different temperature control tasks in a particularly efficient and situation-matched manner. It can be said that control and/or regulation is carried out in connection with the operating mode.

In particular, the compressor of the refrigeration circuit is currently regulated with the aid of a manipulated variable, which is the setpoint air temperature at the evaporator of the air conditioner, in the case of both HVS cooling operation and air-conditioning cooling operation. The cooling capacity of the refrigeration circuit is thereby adjusted according to the cooling requirement for the interior. In addition, the expansion valve is now actuated as a function of the manipulated variable for the compressor in the case of both HVS cooling operation and air-conditioning cooling operation, or a further manipulated variable is used in the case of HVS cooling operation without additional air-conditioning cooling operation for the compressor, or both. Therefore, the distribution of the cooling power is optimized, starting from the regulation of the compressor according to the theoretical air temperature in the case of simultaneous HVS cooling operation and air-conditioning cooling operation. The first optimization is achieved in that the expansion valve is also controlled as a function of the setpoint air temperature during both the HVS cooling operation and the air-conditioning cooling operation. The second optimization is achieved in that, when the air-conditioning cooling operation is omitted, i.e. when there is an HVS cooling operation without an additional air-conditioning cooling operation, the compressor is regulated as a function of a further manipulated variable which is not currently provided for the air-conditioning cooling operation, as is the case with the theoretical air temperature, but rather is provided for the HVS cooling operation. Preferably, both optimizations are combined. Overall, the distribution of the refrigeration power is thus improved in the case of a high-pressure accumulator cooled with coolant competing with the cooling of the interior.

The invention is based on the idea, inter alia, of enabling the operation of a refrigeration circuit to be optimally matched to the tempering requirements at a given point in time by switching the actuation of the refrigeration circuit. Instead of operating the refrigeration circuit independently of the operating mode of the thermal system, it is now advantageously possible to distinguish in which combination the different operating modes are active. In response to this, the respective regulator or the respective control is activated. In this way, the conflict of objectives between the various temperature control requirements can be advantageously resolved. Furthermore, it is advantageously possible to prioritize one particular operating mode over another depending on the overall situation of the thermal system. A further advantage is, in particular, that for a given overall situation, in particular in the case of activation of only one single operating mode, but also in general, a correspondingly optimum regulation of the refrigeration circuit takes place.

The term "control system" is also understood to mean a control system or a control and regulation system. Likewise, the term "control" is currently understood in general and also includes "regulation", as long as it is not explicitly stated otherwise. "tempering" is currently understood to mean cooling, heating or both. Accordingly, the cooling requirement and the heating requirement are also generally referred to as tempering requirements.

Overall, the behavior of the thermal system is decisively determined by the temperature control requirements, which are generated, for example, by specific user inputs via the operating elements of the control system or which take into account the environmental conditions, which are determined by means of suitable sensors of the control system, for example temperature sensors for measuring the outside temperature or the temperature in the vehicle interior, the temperature of the vehicle high-pressure accumulator or the temperature at specific points of the thermal system. Alternatively or additionally, the temperature control requirement for the control system is determined by a higher-level main control system, for example an air conditioning function logic. In this case, the control system described here is in particular a subsystem of a superordinate main control system.

Of particular importance are temperature control requirements with regard to the vehicle interior, for example heating requirements of the user, and in particular in the case of electric or hybrid vehicles, temperature control requirements with regard to the high-pressure accumulator. In particular, the temperature control requirements arise as a function of the external temperature which is a manifestation of weather and environmental conditions. The individual components and the entire thermal system itself are automatically, in a desired and optimum manner controlled and regulated by means of a suitable control and regulation design for operating the thermal system (in particular the refrigeration circuit in the present case) by appropriately correlating the temperature control requirements in the form of predefined or determined parameters describing the temperature control requirements by means of the control system. In principle, the entire heat system can be considered as part of the control system, but at least some components of the heat pump system are part of the control system.

Refrigerant circulates in the refrigeration circuit. The compressor of the refrigeration circuit is in particular an electric refrigerant compressor, EKMV for short. The compressor is disposed downstream of the air conditioner evaporator and radiator and particularly upstream of the condenser. The radiator and the air conditioning evaporator each function as an evaporator and transfer heat into the refrigeration circuit, while the condenser serves to draw heat out of the refrigeration circuit. The evaporators are expediently connected in parallel with one another in the refrigeration circuit and can thus be traversed by refrigerant independently of one another. Upstream of the respective evaporator, an expansion valve is provided, which is opened for activating the evaporator and closed for deactivating the evaporator. Hereinafter, the "expansion valve" is understood as an expansion valve upstream of the radiator as long as it is not otherwise described.

The high-voltage accumulator serves to supply the electric drive of the vehicle with electrical energy and is configured accordingly. In general, the high-voltage reservoir has a plurality of battery cells, which are electrically connected to each other. In addition, it is also possible in particular to remove electrical energy from the high-voltage accumulator for supplying other vehicle components with electrical energy. Alternatively, the high-voltage reservoir is also referred to as an accumulator or a battery.

Currently, the high-pressure accumulator is cooled with coolant and for this purpose is connected in particular to the overall cooling circuit of the thermal system and is cooled in HVS cooling operation by means of a radiator. The overall cooling circuit serves to circulate a coolant, for example a water/glycol mixture, and the high-pressure reservoir is therefore cooled with the coolant and, depending on the temperature control of the coolant, is also heated, if necessary, in particular. The high-pressure accumulator is provided in an HVS circuit, which is part of the overall cooling circuit. Likewise, a radiator is provided in the HVS circuit, suitably downstream of the high pressure reservoir. By activating the radiator, that is to say by opening the expansion valve, heat is transferred from the HVS circuit into the refrigeration circuit and the high-pressure reservoir is cooled. Preferably, the HVS circuit can be shut off with respect to the remaining total cooling circuit, so that in the shut off state the coolant in the HVS circuit does not mix with the coolant from the remaining total cooling circuit. On the contrary, the coolant exchange is performed in the connected state. In particular, an ambient cooler is arranged in the cooling circuit of the overall cooling circuit in order to exchange heat with the environment. In the connected state, the high-pressure accumulator is then cooled via the ambient cooler. A combined cooling can also be achieved both by means of the ambient cooler and by means of the radiator, in particular in that the thermal system is adjusted in such a way that the high-pressure reservoir, the radiator and the ambient cooler are connected in series.

Air conditioning evaporators are in particular part of air conditioning appliances for vehicles. Another part of the air conditioning system is in particular a heating heat exchanger, which is preferably arranged in the heating circuit of the overall cooling circuit. The heating circuit can in particular be operated independently of the cooling circuit and the HVS circuit, but is hydraulically connected to the cooling circuit and can be blocked like the HVS circuit in order to exchange or not exchange the coolant with the remaining overall cooling circuit depending on the operating mode. The temperature control requirement for the vehicle interior is brought about by setting to a suitable operating mode as a function of the temperature control requirement. In the case of tempering requirements including cooling requirements, the interior space is cooled by means of an air-conditioning evaporator. In the case of tempering requirements including heating requirements, the interior space is heated by means of a heating heat exchanger. In the case of a dehumidification request for dehumidifying the internal space, there is a simultaneous heating request and cooling request. Also suitable are designs in which different regions or areas of the interior space, for example the foot space and the ventilation plane, are subjected to different air conditioning, in which case, as a rule, not only heating requirements but also cooling requirements are then present. The air conditioning evaporator and the heating heat exchanger are in particular arranged jointly in an air path through which, in operation, the interior air, that is to say the air supplied to the interior, flows. The interior air exchanges heat with the air conditioning evaporator and the heating heat exchanger depending on the operating mode. The air path can preferably be blocked, wherein the temperature of the interior space is not regulated in the blocked state.

In an advantageous embodiment, the control system is designed such that, in the event of a heating requirement for the interior of the vehicle, an air-conditioning heating mode of the thermal system is set in which heat is transferred to a heating circuit of the thermal system for heating the interior by means of a heat pump, wherein the heat pump is formed by a radiator in combination with a condenser in the heating circuit. In particular, the heating heat exchanger in the above-mentioned heating circuit is supplied with heat via a heat pump. Alternatively, it is also suitable to heat the interior air directly by means of a condenser. The radiator is arranged in the HVS circuit and generally outside the heating circuit, and the condenser is arranged in the heating branch, preferably upstream of the heating heat exchanger.

In order to circulate the coolant in the overall cooling circuit, in particular to connect suitable pumps, it is preferred to connect an own pump in each of the individual circuits of the overall cooling circuit, i.e. to connect the cooling circuit pump in the cooling circuit, to connect the heating circuit pump in the heating circuit and to connect the HVS circuit pump in the HVS circuit.

Preferably, in the event of a cooling requirement for the interior space without an additional heating requirement for the interior space, the heating circuit is opened, the radiator of the heat pump is deactivated and in this way the air-conditioning cooling operation is set. The air conditioning evaporator absorbs heat from the interior air, which is transferred via the condenser into the heating circuit and from there to the ambient cooler in the cooling circuit and to the environment. In the case of a heating requirement and without an additional cooling requirement, the heating circuit is closed, the heating heat exchanger is supplied with heat via the condenser of the heat pump and in this way the air conditioning heating operation is set. The heat here preferably comes from the environment and is absorbed via an ambient cooler or from a component connected to the overall cooling circuit and used as a heat source. Alternatively or additionally to this, it is also expedient if, in order to heat the interior, the waste heat of the high-pressure accumulator is transferred into the heating circuit by means of the heat pump in the air-conditioning heating mode, in particular when the high-pressure accumulator is to be cooled.

A particular challenge is in particular the simultaneous cooling of the high-pressure accumulator and the interior space, since in this case both the HVS cooling operation and the air-conditioning cooling operation are active and therefore both evaporators are operated simultaneously in the refrigeration circuit. In this case, the air-conditioning evaporator and the radiator compete for the refrigeration power, which is applied by the refrigeration circuit, in particular by the compressor. The compressor operates at a specific compressor speed. The compressor speed is adjustable in order to adjust the total available refrigeration power. The distribution of the cooling power to the air-conditioning evaporator and the radiator is produced by the opening of two expansion valves upstream of the air-conditioning evaporator and the radiator. In the present case, the radiator is preferably connected upstream with an expansion valve, abbreviated as EXV, which can be electrically shut off and controlled. The air conditioning evaporator is preferably connected upstream with a thermal expansion valve, TXV for short, which is simple and cost-effective compared to the aforementioned expansion valve. The use of other expansion valves or combinations is in principle possible.

At present, it is expedient to distinguish between the two cases, namely the combined operation of the two evaporators with simultaneous HVS cooling operation and air-conditioning cooling operation, and the operation of only the radiator, that is to say in particular the heat pump, with HVS cooling operation and without air-conditioning cooling operation.

In an advantageous embodiment, the control system is designed such that, when the HVS cooling mode is set, but the air-conditioning cooling mode is not set, the expansion valve is controlled with the superheat of the refrigerant in the refrigeration circuit as a control variable. For this purpose, the control system has a corresponding regulator. In pure HVS cooling operation (i.e. no air-conditioning cooling operation), in particular all the refrigeration power is used for cooling the high-pressure accumulator. The refrigeration capacity itself is set, in particular, by means of the compressor speed, preferably likewise within the range of regulation, as has already been described above. The superheat as a manipulated variable is then used to adjust the expansion valve as a function of the theoretical superheat as a reference variable. The opening degree of the expansion valve is used as an adjustment variable. By adjusting the expansion valve, the specific superheat of the refrigerant upstream of the compressor and thus the refrigerant mass flow and ultimately the power of the heat pump, that is to say the amount of heat transferred by the heat pump from the refrigeration circuit into the heating branch, is adjusted accordingly. The air conditioning evaporator is deactivated here, in particular in such a way that the relevant expansion valve is blocked, that is to say closed. The same is preferably generally selected when the radiator is active and the air-conditioning evaporator is not active, i.e. in particular also when the heat pump is active in an air-conditioning heating operation, for example for heating an interior space.

In a purely air-conditioning cooling operation (i.e. without HVS cooling operation), the compressor speed and therefore also the cooling capacity are preferably first adjusted as a function of the air temperature, which is also referred to as the actual air temperature. For this purpose, the control system has a corresponding regulator to which the air temperature is supplied as a manipulated variable and the setpoint air temperature as a reference variable. The compressor speed is the manipulated variable. Thus, the cooling power is effectively adjusted according to the cooling requirement for the interior space. The expansion valve of the air conditioning evaporator is in particular not regulated by means of the control system described here, but is expediently not regulated here, but preferably regulated itself and for this purpose, for example, has its own, internal and, for example, temperature-controlled regulator. The expansion valve of the radiator is closed. In the case of a pure air-conditioning heating operation (i.e. without additional HVS cooling operation and without additional air-conditioning cooling operation), the compressor is preferably regulated as a function of the heating circuit temperature, i.e. the temperature of the coolant in the heating circuit upstream of the heating heat exchanger and in particular downstream of the condenser. For this purpose, the control system suitably has a corresponding regulator to which the heating circuit temperature is supplied as a regulating variable and the setpoint heating circuit temperature (also referred to as heating circuit setpoint temperature) is supplied as a reference variable. Here, the compressor rotational speed is the manipulated variable.

However, in the case where both the air-conditioning cooling operation and the HVS cooling operation are active, the expansion valve of the radiator is advantageously adjusted according to the air temperature. For this purpose, the control system is expediently designed such that, in the case of simultaneous HVS cooling operation and air-conditioning cooling operation, the expansion valve is actuated as a function of the manipulated variable for the compressor, in that the difference between the air temperature at the evaporator and the setpoint air temperature is used as the controlled variable for the expansion valve. This difference is also referred to as the control deviation of the air temperature. This is based on the following considerations, among others: in the case of an additional activation of the heat sink, a part of the refrigeration power is used to cool the high-pressure accumulator and, for this reason, is taken away from the interior space. Since the regulation of the compressor is combined with the cooling operation of the air conditioner, corresponding compensation is carried out by increasing the rotational speed of the compressor if necessary. By adjusting the compressor as a function of the air temperature, it is ensured in the first place that the cooling requirements for the interior are optimally addressed. In addition, the high-pressure accumulator is cooled as a function of the air temperature in such a way that optimum cooling of the interior is ensured. Since the refrigeration power is branched off for the high-pressure accumulator, an undesirable loss in the cooling of the interior space can occur, which is avoided by controlling the expansion valve of the radiator as a function of the air temperature. In this way, a certain comfort in the interior is advantageously ensured. In this case, the control of the expansion valve is in particular such that the expansion valve is increasingly opened further during the time when the deviation of the air temperature from the setpoint air temperature is within a maximum deviation. In other words: the difference between the air temperature and the theoretical air temperature determines the degree of opening of the expansion valve and thus the portion of the refrigeration power used to cool the high-pressure accumulator. In this case, the dynamics are implemented in particular for the opening degree such that below a predefined upper limit for the difference, the opening degree does not remain constant but opens more and more. The HVS cooling operation is therefore first arranged behind with respect to the air-conditioning cooling operation.

In an advantageous embodiment, the control system is designed such that, in the case of a combination of an HVS cooling operation and an air-conditioning cooling operation, a minimum opening degree of the expansion valve is set and, starting from the minimum opening degree, the expansion valve is opened further and further, to be precise as a function of the difference between the air temperature and the setpoint air temperature or as a function of the cell temperature of the high-pressure accumulator or as a function of both. In the case of the use of the difference, the difference corresponds to the difference already described above, that is to say the control deviation with respect to the air temperature. As described, the cooling of the high-pressure accumulator is first of all discharged downstream in the case of a combination of cooling operations, as a result of the regulation according to the air temperature. The minimum cooling for the high-pressure accumulator is now advantageously ensured by setting to the minimum opening. The expansion valve is opened at least at the minimum opening degree, that is, when closed, the opening degree is maximally reduced to the minimum opening degree. Starting from the minimum opening degree, the expansion valve is opened further only when the air temperature corresponds to the setpoint air temperature within a reliable deviation and when further cooling is required due to the cell temperature. In this way, it is first ensured that the air-conditioning cooling operation is carried out optimally before the additional cooling capacity is then used for the HVS cooling operation.

In an advantageous embodiment, the air-conditioning cooling operation is prioritized over the HVS cooling operation in that the expansion valve is opened further only when the control deviation of the air temperature is within a maximum deviation. The regulation deviation corresponds to a difference between the air temperature (which is the actual air temperature) and the theoretical air temperature. The maximum deviation gives: it is also possible to accept what degree of deviation in relation to the air temperature and to tolerate what comfort loss in the interior space. Therefore, from the viewpoint of minimum cooling for the high-pressure accumulator, the air-conditioning cooling operation is prioritized first over the HVS cooling operation. The expansion valve of the radiator is opened further only if the cooling requirement for the interior is met, so that more cooling power is supplied to the radiator in order to cool the high-pressure accumulator more strongly, if this is required. If the cooling of the high-pressure accumulator leads to too little cooling of the interior space and thus to large regulating deviations, the opening degree of the expansion valve is reduced above the maximum deviation and the cooling of the high-pressure accumulator is taken back in favor of the interior space cooling.

In an advantageous embodiment, the control system is designed such that, in the event of a cell temperature of the high-voltage reservoir being higher than a maximum temperature, the HVS cooling operation is prioritized over the air-conditioning cooling operation in that the maximum deviation is increased. This serves in particular to protect the high-pressure reservoir from excessive cell temperatures and from the corresponding damaging or aging effects. This is advantageous, for example, to prevent degradation of the high-voltage accumulator or to quickly charge the high-voltage accumulator, since here too much waste heat is usually generated by the high-voltage accumulator. Accordingly, in this case, the HVS cooling operation is suitably prioritized. Above the maximum temperature, the control of the expansion valve is facilitated by raising the permissible control deviation for the air temperature. For example, the control deviation is derived from the overall characteristic curve as a function of the cell temperature. The loss of comfort is consciously tolerated by the modified control in order to protect the high-pressure accumulator. The priority of the air-conditioning cooling operation with respect to the HVS cooling operation is thus cancelled and, in turn, the HVS cooling operation is prioritized over the air-conditioning cooling operation.

In an advantageous embodiment, the expansion valve is not opened further or even closed when the superheat is below the minimum superheat. In an advantageous manner, the protection against the compressor is thereby achieved in such a way that the liquid refrigerant is prevented from penetrating due to too little overheating. This monitoring of the overheating is particularly carried out for the case in which both the HVS cooling operation and the air-conditioning cooling operation are active and the expansion valve is controlled as a function of the air temperature.

Alternatively or in addition to the control of the expansion valve according to the operating mode, the compressor is preferably regulated according to the operating mode. The below-described regulation of the compressor is preferably combined with the above-described regulation of the expansion valve, but in principle it may also be advantageous alone.

In one suitable embodiment, the suction pressure upstream of the compressor in the refrigeration circuit is used as a control variable for controlling the compressor when the HVS cooling operation is set, but not the air-conditioning cooling operation and in particular also not the air-conditioning heating operation. This regulation as a function of the suction pressure is therefore carried out in particular only in a pure HVS cooling operation. In the case of a setting to the air-conditioning cooling mode, in particular independently of whether the HVS cooling mode is active or inactive, the controlled variable for the regulation of the compressor is preferably not the suction pressure, but rather the air temperature at the air-conditioning evaporator as described above. For the regulation according to the suction pressure, the control system has a further regulator. Thus, the adjustment is switched according to the operating mode. If no interior temperature control is required during the HVS cooling operation, the compressor is therefore operated as a function of the suction pressure, i.e. as a function of the pressure of the refrigerant upstream of the compressor. Alternatively, for this case, a simple control by setting to a constant compressor speed or to a compressor speed depending on the external temperature or the cell temperature of the high-pressure reservoir is also suitable. However, the regulation according to the specific suction pressure is more efficient and enables a higher refrigeration power in contrast. In one suitable embodiment, the compressor is operated in pure HVS cooling operation via the suction pressure, and in all other cases via the air temperature at the evaporator of the air conditioner. In any case, however, the compressor speed is the manipulated variable. The suction pressure is measured in particular by means of a pressure sensor upstream of the compressor in the refrigeration circuit.

Instead of the suction pressure regulation, in an advantageous embodiment, the coolant temperature upstream of the high-pressure accumulator is used as a regulating variable for regulating the compressor when the HVS cooling operation is set, but the air-conditioning cooling operation is not set. As in the case of the suction pressure regulation described above, the control variable for the case of adjustment to the air-conditioning cooling mode is the setpoint air temperature at the air-conditioning evaporator. The embodiments with suction pressure as the manipulated variable are likewise generally also suitable for coolant temperature as the manipulated variable. The regulator is modified accordingly for this purpose. In this case, higher efficiency and a required refrigeration capacity are also produced compared to a simple regulation as a function of the rotational speed of the compressor. The coolant temperature upstream of the high-pressure reservoir in the HVS circuit is measured, in particular, by means of a temperature sensor upstream of the high-pressure reservoir in the HVS circuit.

Expediently, in the pure HVS cooling mode, the compressor is regulated by means of a regulator to which the suction pressure or the coolant temperature (i.e. generally the actual value) is supplied as a regulating variable and the setpoint suction pressure or the setpoint coolant temperature (i.e. generally the setpoint value) is supplied as a reference variable. The actual value is measured as described above by means of a suitable sensor. In a particularly simple embodiment, the setpoint value is fixedly predefined. In an advantageous embodiment, however, the control system is designed in such a way that the setpoint value for the compressor regulation is derived from the characteristic map at least when the HVS cooling operation is set and the air-conditioning cooling operation is not set. The overall characteristic curve contains the theoretical value as a function of the external temperature or of the cell temperature of the high-voltage reservoir or of both. The cell temperature is measured, in particular, by means of a temperature sensor in the high-voltage reservoir.

In general, a particularly preferred embodiment results from a combination of the described actuation of the refrigeration circuit, in particular for the expansion valve and the compressor, i.e. in an HVS cooling operation without air-conditioning cooling operation, the expansion valve is adjusted as a function of the superheat of the refrigerant and, in particular, independently of this, the compressor is adjusted as a function of the suction pressure or as a function of the coolant temperature upstream of the high-pressure reservoir. In the case of both HVS cooling operation and air-conditioning cooling operation, the two components are controlled as a function of the air temperature, in particular, in this case the compressor is regulated as a function of the setpoint air temperature at the evaporator, and the expansion valve is controlled as a function of whether the regulating deviation of the air temperature falls below an upper limit and, in particular, how far below it.

In an advantageous embodiment, the control system is designed such that the high-pressure limit is set when the air-conditioning heating mode is set, but not when the air-conditioning cooling mode is set. Expediently, the high-voltage limit is likewise set when the HVS cooling operation is active. The compressor of the refrigeration circuit is limited by a high pressure limit according to the maximum high pressure of the refrigerant downstream of the compressor.

In other words: the compressor is high pressure limited. The compressor is thereby advantageously protected against unreliable operating conditions.

For high-pressure limiting, the compressor is preferably high-pressure limited by means of a combination of characteristic curves, in particular characteristic curves. The overall characteristic curve contains the compressor speed for the compressor as a function of the maximum high pressure. The high pressure for a particular compressor speed is thereby limited to a corresponding maximum high pressure. In particular, the overall characteristic curve contains in particular the compressor speed and not only the limiting factor. The characteristic map is characterized in that the compressor speed decreases as the high pressure increases, so that the compressor speed is set to a lower compressor speed by means of the characteristic map in the event of an increase in the high pressure. The dependence on the high pressure by the characteristic curve thus ensures that the high pressure is not higher than a reliable maximum compressor speed, so that the high pressure does not rise further, but is limited to the maximum high pressure.

Instead of the described overall characteristic curve, the high-pressure limitation is effected by means of a regulator, in particular a sixth regulator, which is also referred to as a limiting regulator and regulates the compressor speed of the compressor such that it is not higher than the maximum high pressure. The regulator is part of the control system. The actual high pressure of the refrigerant downstream of the compressor is supplied as a reference variable to the regulator. The actual high pressure is expediently measured by means of a pressure sensor downstream of the compressor in the refrigeration circuit. The compressor speed is used as a manipulated variable for the limiting regulator. The maximum high pressure, which is fixedly predefined or derived from a characteristic curve, is used as a control variable. In general, unreliable loading of the compressor is avoided by high pressure limitations. This is advantageous in particular in heating operation of the air conditioner with a high theoretical temperature of the heating circuit, for example in winter. Generally, high pressures increase and become less effective as the theoretical temperature of the heating circuit increases when the refrigeration circuit is operating. The extent of this effect depends inter alia on the refrigerant used. However, it is generally expedient to avoid high pressure rises of more than 20 to 24 bar. Other values may also be suitable depending on the application and the specific design of the thermal system.

In a method for operating a thermal system of an electric or hybrid vehicle, an air-conditioning cooling operation of the thermal system is set by means of a control system as described above in the case of a cooling requirement for an interior space of the vehicle for cooling the interior space by means of an air-conditioning evaporator of the thermal system; the method comprises the steps of setting an HVS cooling mode of the thermal system for cooling the high-voltage accumulator by means of a radiator of the thermal system in response to a cooling demand of the high-voltage accumulator of the vehicle, and controlling a component of a refrigeration circuit of the thermal system in accordance with a control variable selected from different control variables depending on whether the cooling mode is set to an air-conditioning cooling mode, or to an HVS cooling mode, or to both.

The object is also achieved, in particular, by an electric or hybrid vehicle having a control system as described above. Furthermore, the object is also achieved in particular by using the control system as described in an electric or hybrid vehicle. In addition, the object is achieved in particular by the combination of a thermal system with a control system as described, wherein the components controlled by the control system are in each case part of the thermal system.

Drawings

Embodiments of the invention are explained in detail below with the aid of the figures. In the drawings:

figure 1 shows a schematic diagram of a thermal system and a control system,

figure 2 shows a schematic diagram of a refrigeration circuit of a thermal system,

figure 3 shows a schematic view of a variant of the refrigeration circuit,

figure 4 shows a schematic diagram of the regulation design for the expansion valve of a thermal system,

fig. 5 shows a schematic diagram of a regulation scheme for a compressor of a thermal system.

Detailed Description

Fig. 1 shows a thermal system 2 and a control system 4 for controlling various components of the thermal system 2. The thermal system 2 is configured for use in an electric or hybrid vehicle, also referred to merely as a vehicle, which is not shown in detail. The thermal system 2 has a main cooling circuit 6 and a refrigerating circuit 8, which is not shown in fig. 1. Two variants of the refrigerating circuit 8 are shown in fig. 2 and 3. The thermal system 2 in fig. 1 constitutes a preferred embodiment.

The overall cooling circuit 6 has in the embodiment shown a plurality of

circuits

10, 12, 14, namely a cooling circuit 10, an HVS circuit 12 and a heating circuit 14. A high voltage accumulator 16 is connected to the HVS circuit 12 for powering an electric drive train of an electric or hybrid vehicle. Furthermore, the HVS heater 18 is connected to the HVS circuit 12, but in a variant which is not shown, it is dispensed with. Furthermore, a radiator 20 is connected to the HVS circuit 12, which radiator is also connected to the refrigeration circuit 8. Further, an HVS circuit pump 22 is provided in the HVS circuit 12 for circulating the coolant. The high-pressure reservoir 16 is filled fluidically by means of an unillustrated HVS shutoff valve in combination with an likewise unillustrated HVS check valve.

A heat source 24 of the vehicle is connected to the cooling circuit 10. The heat source 24 is, for example, an electric motor or power or charging electronics of the vehicle. Downstream of the heat source 24, a first ambient cooler 26 is connected to the cooling circuit 8 for heat exchange with the environment. The first ambient cooler 26 is combined with the second ambient cooler 28 in the illustrated embodiment into a cooler group. In principle, however, a design without the second ambient cooler 28 is also possible. Furthermore, a cooling circuit pump 30 is provided in the cooling circuit 10, here downstream of the first ambient cooler 26 and upstream of the heat source 24.

The heating circuit 14 serves to temper the interior space. A heating heat exchanger 32 is connected to the heating circuit 14 for heating interior space air for an interior space 34 of the vehicle. Furthermore, a condenser 36 is connected to the heating circuit 14, which condenser is also connected to the refrigeration circuit 8 and forms, together with the radiator 20, a heat pump configured for transferring heat from the radiator 20 into the heating circuit 14. Further, a heating circuit pump 38 and a heater 40 are provided in the heating circuit 14. In the embodiment shown, the condenser 36, the heating circuit pump 38, the heater 40 and the heating heat exchanger 32 are arranged in the main circuit of the heating circuit 14 downstream of one another in the mentioned order. The recirculation line via the heating circuit 14 closes the circuit and enables circulation of the coolant. Only one non-return valve, not specified in detail, is provided in the recirculation line. The heating circuit 14 is connected to the cooling circuit 10 via a heating circuit feed line 42 and a heating circuit return line 44 in such a way that the main line and the components connected thereto are arranged in series with the first ambient cooler 26.

The HVS circuit 12 is likewise attached to the cooling circuit 8, but not to the heating circuit 14. The HVS loop 12 is connected upstream and downstream of the heat source 24 and downstream of the heat sink 20. Thereby, series or parallel connection of the high-pressure reservoir 16 and the heat source 24 can be selectively achieved.

Downstream of the first ambient cooler 26, a cooler branch 46 is formed, from which an NT branch 48 and an HT branch 50 extend, wherein the HT branch 50 forms a feed line for the heat source 24 and the NT branch 48 is connected downstream of the radiator 20 to the HVS circuit 12. Upstream of the HVS circuit 12, a second ambient cooler 28 is also connected to the NT branch 48. The heating circuit 14 is furthermore currently connected to the NT branch 48 via a heating circuit feed line 42.

Furthermore, the thermal system 2 has an equilibrium volume 52 for the coolant. Furthermore, temperature sensors 54 are connected in the overall cooling circuit 2 at various points for measuring the temperature of the coolant.

For the tempering of the interior, the thermal system 2 additionally has an air-conditioning evaporator 56, which is connected to the refrigeration circuit 8.

As shown in fig. 2 and 3, the air conditioning evaporator 56 is connected in parallel with the radiator 20 in the refrigeration circuit 8. To adjust the cooling capacity of the air-conditioning evaporator 56, an expansion valve 58 is connected upstream thereof. An expansion valve 60 is also connected upstream to the radiator 20. The heating heat exchanger 32 and the air conditioning evaporator 56 together form an air conditioning unit, by means of which both the interior 34 can be heated and cooled and also dehumidified.

In the variant of fig. 2 and 3, the refrigeration circuit 8 has a compressor 62, a plurality of evaporators, namely an air-conditioning evaporator 56 and a radiator 20, and also a condenser 36. The refrigeration circuit 8 in fig. 2 additionally has two internal heat exchangers 64, one internal heat exchanger for each of the air-conditioning evaporator 56 and the radiator 20. In the variant of fig. 3, only one internal heat exchanger 64 is provided for both evaporators. Downstream of the air conditioning evaporator 56, a non-specified non-return valve is provided, which in the variant of fig. 2 can also be provided upstream of the internal heat exchanger 64. In a variant that is not shown, the internal heat exchanger 64 is not present.

In order to switch the thermal system 2 between the various switching states and to adjust to the different operating modes,

different valves

66, 68, 70, 72 are provided in the overall cooling circuit 4. A shut-off valve 66 in the heating circuit feed line 42 serves to shut off the heating circuit 14, i.e. to open or to close the same. Alternatively, the shut-off valve 66 is provided in the heating circuit return line 44. Furthermore, three 3/2

way valves

68, 70, 72 are provided, which 3/2 way valves enable various series and parallel connections of the first ambient cooler 26, the radiator 20, the heat source 24 and the high-pressure accumulator 16 depending on the switching position. Thus, for example, an HVS heating operation can be realized in which the radiator 20, the heat source 24, and the high-pressure reservoir 16 are connected in series. It is also possible to realize a series configuration including the radiator 20 and the high-pressure reservoir 16, and in parallel therewith and independently, a series configuration including the heat source 24 and the first ambient cooler 26 for the HVS cooling operation and the heat source cooling operation, respectively. Furthermore, a series arrangement comprising a heat source 24, a radiator 20 and a first ambient cooler 26 can be realized, wherein the high-pressure reservoir 16 is then connected in parallel with the first ambient cooler 26 and with the heat source 24. Additionally, a switching state may also be achieved in which the heat source 24 is connected in parallel with the series arrangement comprising the second ambient cooler 28, the radiator 20 and the high-pressure reservoir 16. The heating circuit 14 can be switched off independently of this.

The control system 4 is designed such that, in the event of a cooling request for the interior 34, an air-conditioning cooling operation of the thermal system 2 is set for cooling the interior by means of the air-conditioning evaporator 56, and in the event of a cooling request for the high-pressure reservoir 16, an HVS cooling operation is set for cooling the high-pressure reservoir 16 by means of the radiator 20. The components of the thermal system 2 required for this purpose are correspondingly controlled by means of the control system 4. The air-conditioning cooling operation and the HVS cooling operation are each one operation mode of the thermal system 2. Furthermore, the refrigeration circuit 8 is operated depending on whether it is adjusted to the air-conditioning cooling operation, the HVS cooling operation, or both. In the illustrated embodiment, the compressor 62 and the expansion valve 60 of the radiator 20 are operated as required depending on which operating modes are activated.

In addition to the HVS cooling operation and the air-conditioning cooling operation, the heating circuit 14 can also be used to set an air-conditioning heating operation for the thermal system 2. In the air-conditioning heating mode, heat is transferred into the heating circuit 14 by means of a heat pump in order to heat the interior. In a variant that is not shown, the interior air is heated directly by means of the condenser 36. In the case of a cooling requirement for the interior 34, this interior is cooled by means of the air conditioning evaporator 56. In case of a heating requirement, the interior space 34 is heated by means of the heating heat exchanger 32. In the case of a dehumidification request for dehumidifying the internal space 34, there is a simultaneous heating request and cooling request. The air-conditioning evaporator 56 and the heating heat exchanger 32 are arranged jointly in an air path, not shown in detail, through which, in operation, interior air, that is to say air supplied to the interior, flows. The interior air exchanges heat with the air conditioning evaporator 56 and the heat exchanger 32, depending on the mode of operation.

In the event of a cooling requirement for the interior 34 without an additional heating requirement for the interior 34, the heating circuit 14 is opened, the heat pump radiator 20 is deactivated and in this way the air-conditioning cooling operation is set. The air conditioning evaporator 56 absorbs heat from the interior air, transfers said heat via the condenser 36 into the heating circuit 14 and from there to the

ambient coolers

26, 28 in the cooling circuit 8 and to the environment. In the event of a heating requirement and no additional cooling requirement, the heating circuit 14 is closed, heat is supplied to the heating heat exchanger 32 via the condenser 36 of the heat pump, and the air-conditioning heating operation is set in this way. In this case, the heat is taken from the environment and is absorbed via the

environment coolers

26, 28 or from components connected to the overall cooling circuit 6, for example from the high-pressure reservoir 16, the HVS heater 18 or the heat source 24.

The simultaneous cooling of the high-pressure accumulator 16 and the interior 34 is a particular challenge, since in this case both the HVS cooling operation and the air-conditioning cooling operation are active and therefore both evaporators are operated simultaneously in the refrigerating circuit 8. In this situation, the air conditioner evaporator 56 and the radiator 20 compete for the cooling power applied by the compressor 62. The compressor 62 is operated at a specific compressor speed VD which can be adjusted by means of the control system 4 in order to adjust the total available refrigeration power. The distribution of the refrigeration power to the air-conditioning evaporator 56 and the radiator 20 is produced by the opening of the two

expansion valves

58, 60. Currently, the radiator 20 is connected upstream to an expansion valve 60, abbreviated to EXV, which can be electrically shut off and controlled. While the air conditioning compressor 56 is connected upstream to a thermal expansion valve 58, TXV for short, which is simple and cost-effective compared to the aforementioned expansion valves.

The control of the expansion valve 60 by the control system 4 as a function of the active operating mode is illustrated in fig. 4. In the case of adjusting to the combination of the HVS cooling operation and the air-conditioning cooling operation, the difference between the air temperature T-KV-I at the air-conditioning evaporator 56 and the theoretical air temperature T-KV-S is used as the control parameter for the controller R1. In the case of setting to the HVS cooling mode, but not to the air-conditioning cooling mode, the superheat u-I of the refrigerant in the refrigerating circuit 8 is used as the manipulated variable for the regulator R2. The relevant reference variable corresponds to the theoretical superheat u-S, which is derived, for example, from a comprehensive characteristic curve, not shown in detail, as a function of one or more further parameters.

In pure HVS cooling operation (i.e., no air conditioning cooling operation), all of the refrigeration power is used to cool the high-pressure accumulator 16. The refrigeration capacity itself is set by means of the compressor speed VD, which is also currently set within the scope of the regulation as shown in fig. 5 and explained in more detail below. The expansion valve 60 is then adjusted with the superheat u-I as the manipulated variable in accordance with the theoretical superheat u-S as the reference variable. The opening degree of the expansion valve 60 is used as an adjustment parameter. At this time, the air conditioner evaporator 56 is deactivated in such a manner that the relevant expansion valve 58 is shut off.

In the case of a purely air-conditioning cooling operation (i.e. without HVS cooling operation), the compressor rotational speed VD and thus also the refrigeration capacity are initially preferably set in relation to the air temperature T-KV-I. The cooling power is effectively adjusted according to the cooling requirements for the interior space 34. The expansion valve 58 of the air conditioner evaporator 56 is not regulated here. The expansion valve 60 of the radiator 20 is closed.

However, in the case where both the air-conditioning cooling operation and the HVS cooling operation are activated, the expansion valve 60 is adjusted according to the air temperature T-KV-I. Since the regulation of the compressor 62 is combined with the air-conditioning cooling operation, corresponding compensation is carried out by increasing the compressor rotational speed VD if necessary. By adjusting the compressor 62 in accordance with the air temperature T-KV-I, it is ensured in the first place that the cooling requirements for the interior 34 are optimally addressed. In addition, the high-voltage accumulator 16 is cooled as a function of the air temperature T-KV-I in such a way that optimum cooling of the interior is ensured. By controlling the expansion valve 60 as a function of the air temperature T-KV-I, undesirable losses in the cooling of the interior space due to the refrigeration power split for the high-pressure accumulator 16 are avoided. The HVS cooling operation is therefore first arranged behind the air-conditioning cooling operation.

For the case of adjusting to a combination of HVS cooling operation and air-conditioning cooling operation, that is to say when the control R1 is activated, in the illustrated embodiment of fig. 4, the minimum opening degree of the expansion valve 60 is adjusted

The controller R1 is not below the minimum opening. By adjusting to a minimum opening degree

Ensuring minimal cooling for the high pressure reservoir 16. From minimum opening

Starting from the theoretical air temperature T, the air temperature T-KV-I is within the toleranceKV-S and when further cooling is required due to the cell temperature, the expansion valve 60 is opened further. Thereby, it is ensured that the air-conditioning cooling operation is carried out optimally before the additional cooling power is then used for the HVS cooling operation.

Generally, air conditioning cooling operation is currently prioritized over HVS cooling operation by further opening the expansion valve 60 only when the regulation deviation of the air temperature T-KV-I is within the maximum deviation dKV-max. The adjustment deviation corresponds to the difference between the air temperature T-KV-I and the theoretical air temperature T-KV-S. The maximum deviation dKV-max gives: it is also possible to accept what degree of deviation and to tolerate what loss of comfort in the inner space 34. Thus, the high-pressure accumulator 16 is controlled by the minimum opening degree

The minimum cooling to be achieved is initiated by first giving priority to the air-conditioning cooling operation over the HVS cooling operation. The further opening of the expansion valve 60 provides more cooling power to the radiator 20 in order to cool the high-pressure reservoir 16 more strongly if the cooling requirement for the interior 34 is fulfilled.

If the cell temperature T-Z of the high-voltage reservoir 16 is higher than the maximum temperature T-Zmax, the HVS cooling operation is in turn prioritized over the air-conditioning cooling operation in such a way that the maximum deviation dKV-max is increased. This serves to protect the high-voltage reservoir 16 from excessive cell temperatures and from the corresponding damaging or aging effects. Above the maximum temperature T-Zmax, the control of the expansion valve 60 is facilitated by raising the permissible control deviation for the air temperature T-KV-I. In other words: the maximum deviation dKV-max is increased and is derived, for example, from a characteristic curve, not shown in detail, as a function of the cell temperature T-Z.

As illustrated in fig. 4, currently, when overheated

Below minimum superheat

When the expansion valve 60 is not opened further or even closed.

In the illustrated embodiment, the compressor 62 is also regulated depending on the mode of operation. The adjustment shown is based on the adjustment shown in fig. 2 in the initially mentioned DE102015218825a1, wherein, however, some details are omitted for the sake of clarity. The compressor speed VD, which is in any case a control variable, decisively determines the power applied by the compressor 62. In principle, the adjustment is first effected via two regulators R3, R4, of which only one regulator is selected. In the case of the air-conditioning cooling operation or the combination of the air-conditioning cooling operation and the air-conditioning heating operation, a regulator R3 is used, which regulates the compressor 62 in accordance with the air temperature T-KV-I at the air-conditioning evaporator 56. Whereas in the case of pure air conditioning heating operation the regulator R4 is used, which regulates the compressor 62 in dependence on the heating circuit temperature T-HK-I, which gives the temperature of the coolant in the heating circuit 14 between the condenser 36 and the heating heat exchanger 32. Accordingly, the theoretical air temperature T-KV-S or the theoretical heating circuit temperature T-HK-S is used as a reference variable. In a variant that is not shown, as in DE102015218825a1 in fig. 2, an additional regulator is additionally present for regulating the compressor 62 as a function of the temperature of the coolant outside the heating circuit 14, for example downstream of the radiator 20 and upstream of the

ambient coolers

26, 28. Icing of the

ambient coolers

26, 28 due to excessively strongly cooled coolant in the radiator 20 is effectively prevented by the additional control section by reducing the compressor rotational speed VD in time. This additional regulator is then the limiting regulator for regulator R4, i.e. it only functions in pure air conditioning heating operation.

Additionally, fig. 5 shows a further regulator R5, which is used when the HVS cooling operation is set, but not the air-conditioning cooling operation and also not the air-conditioning heating operation. The control variable is in the first variant the suction pressure P-I in the refrigeration circuit 8 upstream of the compressor 62. In a second variant, the manipulated variable is the coolant temperature T-HVS-I upstream of the high-pressure accumulator 16. If no interior space tempering is required during the HVS cooling operation, the compressor 62 is therefore operated as a function of the suction pressure P-I or as a function of the coolant temperature T-HVS-I. The suction pressure P-I is measured by means of a pressure sensor 74 located upstream of the compressor 62 in the refrigeration circuit 8. The pressure sensor 74 is here even a pressure and temperature sensor. The coolant temperature T-HVS-I is measured, if necessary, by means of a temperature sensor 54 upstream of the high-pressure accumulator 16. The setpoint suction pressure P-S or the setpoint coolant temperature T-HVS-S is supplied to the regulator R5 as a reference variable. As shown in FIG. 5, the respective setpoint values P-S, T-HVS-S are currently derived from a characteristic curve K1 which contains the setpoint values PS, T-HVS-S as a function of the external temperature T-a and the cell temperature T-Z.

In addition, a high-voltage limit is also currently implemented, which is adjusted when the air-conditioning heating operation is adjusted, but the air-conditioning cooling operation and the HVS cooling operation are not adjusted. The regulation of the compressor 62 is limited by a high pressure limit according to the maximum high pressure HP-max of the refrigerant downstream of the compressor 62. Thereby protecting the compressor 62 from unreliable operating conditions. The compressor 62 is currently high-pressure-limited by means of a characteristic curve K2 which contains the compressor rotational speed VD as a function of the high pressure HP. The high pressure HP associated with this particular compressor speed VD is then the maximum high pressure HP-max. In particular, the characteristic curve K2 contains the compressor speed VD, which decreases as the high pressure HP increases, so that the low compressor speed VD is set by means of the characteristic curve K2 with increasing high pressure HP. The high pressure HP is measured by means of a pressure sensor 76 in the refrigeration circuit 8 downstream of the compressor 62. The pressure sensor 76 is here configured as a combined pressure and temperature sensor. In a variant that is not shown, a regulator is used instead of the characteristic curve K2 to limit the high pressure.

List of reference numerals

2 thermal system

4 control system

6 Total Cooling Circuit

8 refrigeration circuit

10 cooling circuit

12 HVS circuit

14 heating circuit

16 high pressure accumulator

18 HVS heater

20 radiator

22 HVS loop pump

24 heat source

26 first ambient cooler

28 second ambient cooler

30 cooling circuit pump

32 heating heat exchanger

34 inner space

36 condenser

38 heating loop pump

40 heater

42 heating circuit feed-in tube

44 return pipe of heating circuit

46 cooler branch

48 NT branch

50 HT branch

52 balance volume

54 temperature sensor

56 air-conditioning evaporator

58 (of air-conditioning evaporator) expansion valve

60 (of radiator) expansion valve

62 compressor

64 internal heat exchanger

66 stop valve

683/2 through valve

703/2 through valve

723/2 through valve

74 pressure sensor

76 pressure sensor

dKV-max maximum deviation

HP high pressure

HP-max maximum high pressure

K1 comprehensive characteristic curve

K2 comprehensive characteristic curve

Minimum opening degree

P-I suction pressure

P-S theoretical suction pressure

R1 controller

R2 regulator

R3 regulator

R4 regulator

R5 regulator

T-a external temperature

T-HK-I heating loop temperature

Theoretical temperature of T-HK-S heating loop

T-HVS-I coolant temperature

T-HVS-S theoretical Coolant temperature

T-KV-I air temperature

T-KV-S theoretical air temperature

Temperature of T-Z battery cell

T-Zmax maximum temperature

Superheating

Minimum superheat

Theoretical superheat

Rotational speed of VD compressor

Claims

1. A control system (4) for a thermal system (2) of an electric or hybrid vehicle having a high-pressure accumulator (16) cooled with coolant, the control system being designed such that

Adjusting to an air-conditioning cooling operation in the event of a cooling requirement for an interior (34) of the vehicle for cooling the interior by means of an air-conditioning evaporator (56) of a refrigeration circuit (8) of the thermal system (2);

adjusting to an HVS cooling mode in response to a cooling request for a high-pressure accumulator (16) of a vehicle for cooling the high-pressure accumulator (16) by means of a radiator (20) having an expansion valve (60) connected upstream in the refrigeration circuit (8);

-regulating the compressor (62) of the refrigeration circuit (8) by means of a regulating variable in the case of simultaneous HVS cooling operation and air-conditioning cooling operation, the regulating variable being the setpoint air temperature (T-KV-S) at the air-conditioning evaporator (56); and

the expansion valve (60) is actuated as a function of a manipulated variable for the compressor (62) in the case of simultaneous HVS cooling and air-conditioning cooling, or a further manipulated variable is used in the case of HVS cooling without additional air-conditioning cooling for the compressor (62), or both.

2. Control system (4) according to claim 1, wherein the control system is configured such that the superheating of the refrigerant in the refrigeration circuit (8) is performed with adjustment to the HVS cooling operation but without adjustment to the air-conditioning cooling operation

The expansion valve (60) is regulated as a regulating variable.

3. Control system (4) according to one of claims 1 or 2, wherein the control system is configured such that the expansion valve (60) is actuated as a function of the manipulated variable for the compressor (62) in the case of simultaneous HVS cooling operation and air-conditioning cooling operation in that the difference between the air temperature (T-KV-I) at the evaporator (56) and the setpoint air temperature (T-KV-S) is used as the controlled variable for the expansion valve (60).

4. A control system (4) according to claim 3, wherein the control system is configured to prioritize the air-conditioning cooling operation over the HVS cooling operation in such a way that the expansion valve (60) is further opened only if the difference is within a maximum deviation (dKV-max).

5. The control system (4) according to claim 4, wherein the control system is configured such that, in the case where the cell temperature (T-Z) of the high-voltage reservoir (16) is higher than a maximum temperature (T-Zmax), the HVS cooling operation is prioritized over the air-conditioning cooling operation in such a manner that the maximum deviation (dKV-max) is increased.

6. The control system (4) according to any one of claims 1 to 5, wherein the control system is configured such that, in the case of adjusting to the HVS cooling operation in combination with the air-conditioning cooling operation, the minimum opening degree to the expansion valve (60) is adjusted

And from said minimum opening

Starting from there, the expansion valve (60) is opened more and more, specifically, according to the difference between the air temperature (T-KV-I) and the setpoint air temperature (T-KV-S) or according to the cell temperature (T-Z) of the high-pressure reservoir (16) or both.

7. The control system (4) of any of claims 1 to 6, wherein the control system is configured such that when refrigerant in the refrigeration circuit (8) is presentIs overheated

Below minimum superheat

When the expansion valve (60) is not opened further or even closed.

8. The control system (4) according to any one of claims 1 to 7, wherein the control system is configured such that, in the event of an adjustment to the HVS cooling operation, but not to the air-conditioning cooling operation, for regulating the compressor (62), a suction pressure (P-I) upstream of the compressor (62) in the refrigeration circuit (8) is used as a regulating variable.

9. The control system (4) as claimed in one of claims 1 to 7, wherein the control system is configured such that, in the event of an adjustment to the HVS cooling operation, but not to the air-conditioning cooling operation, for regulating the compressor (62), a coolant temperature (T-HVS-I) upstream of the high-pressure reservoir (16) is used as a regulating variable.

10. Control system (4) according to any one of claims 8 or 9, wherein the control system is configured such that, at least in the case of adjustment to the HVS cooling operation and without adjustment to the air-conditioning cooling operation, a setpoint value (P-S, T-HVS-S) for regulating the compressor (62) is derived from a comprehensive characteristic curve (K1) which contains the setpoint value (P-S, T-HVS-S) as a function of the external temperature (T-a) or of the cell temperature (T-Z) of the high-voltage reservoir (16) or of both.

11. The control system (4) as claimed in one of claims 1 to 10, wherein the control system is configured such that an air-conditioning heating operation to the thermal system (2) is adjusted in the case of a heating requirement for an interior space (34) of a vehicle for heating the interior space by means of a heating circuit (14) of the thermal system (2); and adjusting to a high pressure limit if the air conditioning heating operation is adjusted but not the air conditioning cooling operation, wherein by the high pressure limit the compressor (62) of the refrigeration circuit (8) is limited according to a maximum high pressure (HP-max) of the refrigerant downstream of the compressor (62).

12. The control system (4) as claimed in claim 11, wherein the control system is configured such that, for the high-pressure limitation, the compressor (62) is high-pressure limited by means of a characteristic curve (K2), wherein the characteristic curve (K2) contains a compressor rotational speed (VD) for the compressor (62) as a function of the maximum high pressure (HP-max).

13. A control system (4) according to claim 11, wherein the control system is configured such that the high pressure limit is achieved by means of a regulator which regulates the compressor rotational speed (VD) of the compressor (62) such that it is not higher than a maximum high pressure (HP-max).

14. Method for operating a thermal system (2) of an electric or hybrid vehicle by means of a control system (4) according to one of claims 1 to 13, wherein the control system (4)